Did you seriously look at the FAQ of the vegan society, picked something that confirmed your preestablished opinion, and ignored the sentence right before it?

Here, let me show the whole quote:

What does it mean to be vegan?

A vegan lifestyle involves living a life that is more compassionate towards animals and the environment. The precise definition of veganism is:

"Veganism is a philosophy and way of living which seeks to exclude – as far as is possible and practicable – all forms of exploitation of, and cruelty to, animals for food, clothing or any other purpose; and by extension, promotes the development and use of animal-free alternatives for the benefit of animals, humans and the environment. In dietary terms it denotes the practice of dispensing with all products derived wholly or partly from animals."

You just have a very superficial view of veganism. Just ask yourself this: Why abstain from animals products? What is the intention of a vegan lifestyle? You've claimed that a nuanced application would have "made a religion", but the opposite is true. It would be a religion if we'd blindly apply a rule of conduct without any considerations. Which we don't, as you will see all over the vegan society's website. Just check what they write about animal products in medication. They are absolutely clear how a vegan lifestyle should work: "As far as is possible and practicable." An important principle that practically every single vegan out there knows and lives by.